With increasing development of personal computers and networks, the services provided through networks are becoming more and more appealing in various applications. A data center is a facility used to house computers or servers. For providing intensive network applications, the numbers of computers or servers need to be increased. The precise electronic instruments and facilities installed in the data center need highly reliable power to maintain normal operations. Generally, an uninterruptible power supply (UPS) are widely used to provide uninterruptible and stable power. For example, the UPS becomes essential for network communication appliances, data centers and some important information appliances.
Generally, the uninterruptible power supply includes plural power modules that are connected with each other in parallel. If one of the power modules has a breakdown, the uninterruptible power supply may be normally operated. However, since the capacitance level of the output capacitor at the output side of the power module is very large, once the power module is replaced or removed from the uninterruptible power supply, the output capacitor has a residual voltage. In this circumstance, the user may get an electric shock if the user carelessly touches the power connector.
Moreover, for enhancing the operating efficiency, the output voltage of the power module should be increased to for example 400V. As known, the magnitude of the residual voltage of the output capacitor is in direct proportion to the output voltage of the power module. When the power module of the conventional uninterruptible power supply is replaced or removed, the high residual voltage may result in an arcing problem. For overcoming the arcing problem, the power connector used in the uninterruptible power supply should withstand high temperature and have good insulating properties in order to prevent the arching problem from temporarily damaging the power connector and avoid a short-circuited problem of the power connector. Since the power connector capable of withstanding high temperature and having good insulating properties are not cost-effective, the fabricating cost of the power module and the overall uninterruptible power supply will be increased. Moreover, during the power module is replaced or removed from the uninterruptible power supply, the electrical energy stored in the output capacitor is slowly discharged and exhausted. In other words, the conventional uninterruptible power supply fails to meet the power-saving requirement.
Therefore, there is a need of providing an uninterruptible power supply (UPS) system for avoiding arcing generation so as to obviate the drawbacks encountered from the prior art.